The Joys and Pitfalls of Bee Research

|   Botanik, Ökologie, Landschaft

Johannes Wirz

In the past working year I was busy with three different projects, all of which, at their core, have to do with the survival of bee colonies. The focus in the "forest bee project" is on the question of whether colonies in our forests can still find enough flowers to survive on. In the "heat project", a new method is being tested to eliminate the Varroa mite, the most threatening parasite of honey bees worldwide, from the bee colonies. And in the third project, called "small hives", a new beekeeping practice is being investigated. I would like to present one project in more detail.

The Forest Bee Project

For the past four years we have been reintroducing bee colonies in ten hollowed-out trees and log hives at a height of 4–7 m in the Dorneckberg forest district, a forested area of about 10 km2. So far we've had modest success. A successful reintroduction would be an important contribution to the improvement of biodiversity in the forest, not only because of pollination but also because of the nutrient supply for other animals, since about 20 kg of bees per colony leave the hive to die and thus form an important food source.

Six of the ten hives are equipped with sophisticated sensor technology that not only measures environmental data, but also records the climate inside the colonies. Until now, there have been repeated problems with the power supply and the transmission of the data to a central server.Additionally, the number of mites in the colonies is regularly recorded and honey is harvested whenever possible. The honey is tested for pesticide residues and used for pollen analysis, which allows conclusions to be drawn about the flowering plants visited.

In spring 2022, all (!) colonies died. The cause was not disease but lack of food.

A new start was made. Two dwellings were colonised by swarms that had departed from beekeepers' hives in the surrounding area. It is ironical that they came from colleagues who actually want to prevent swarming. Two more swarms were brought in from my apiary and – a novelty – four colonies were formed from swarms of the dark bee (Apis mellifera mellifera), the breed originally found in Central Europe.

Unlike previous years, all newly formed colonies were fed with 12 kg of sugar (with honey and herbal tea), because studies have shown that 80% of wild colonies in the forest die in the first winter due to lack of food. In the 2nd and 3rd winter, however, the losses drop to an average of 20 %.

The mite load was low in all colonies. Pollen analyses showed that, apart from white clover, hardly any plants in the meagre meadows of the large clearings were flown over, but flowers in the forest were visited: raspberry, blackberry, ivy, monocot goldenrod, asters and water asters. This was one of the reasons why the pesticide residues were below detectable concentrations. Forest edge management, cultivation of hedges and thinning out of forests are being promoted and hopefully form the starting point for the establishment of a stable forest bee population.

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